Beauty might be a matter of dietary makeup

Karen Ravn, Special to the Los Angeles Times

Please don't take this wrong. You look absolutely fine the way you are. It's just that ... well, with a little work, you might look even better.

We're not talking plastic surgery. Just the daily grind of buckling down and trying to eat better. Fresh from the March issue of the journal PLoS ONE comes word that scarfing down a few extra fruits and vegetables — yes, those again — could give you a significant leg up in the attractiveness department.

Scientists have known for a while that the same pigments that give fruits and vegetables their color —carotenoids — can accumulate in your skin and give it color too. What they didn't know was this: How many fruits and vegetables do you have to eat for how long in order for people to notice the difference in your coloring? And what, if anything, will people think of the difference?

Researchers at the University of St. Andrews in Scotland did two studies to try to find out. In the first, they analyzed natural changes in the fruit and vegetable intake of 35 undergraduates who filled out questionnaires about their diet three times: at an initial session, three weeks later and again three weeks after that.

On those same three occasions, researchers measured the students' skin color in terms of lightness, redness and yellowness using a spectrophotometer — a machine designed to do that sort of thing. (To be included in the study, students could not have a recently acquired tan from sun, salon or chemical product, and they could not be wearing facial makeup.)

The researchers didn't ask the students to make any changes in what they ate. And they didn't betray any special interest in any particular foods. But during the six weeks, some students spontaneously increased their produce consumption, and such increases were significantly associated with increased redness, yellowness and overall darkness of skin color. From the machine's perspective anyway.

But that didn't mean mere human beings could detect any difference or would like what they saw if they could.

So the researchers did another study. This time they showed 24 undergrads pictures of two men and two women that had been manipulated color-wise to correspond to how they would look if they ate various quantities of fruits and vegetables.

Students were asked to choose between pairs of faces — 22 were created for each face — according to which looked healthier or, in a separate task, more attractive.

On average, a difference of about 2.9 servings of fruits and vegetables a day was enough for the students to discriminate on the basis of healthy appearance, with more servings associated with looking healthier. Similarly, about 3.3 servings a day was enough for them to discriminate on the basis of attractiveness — with more servings associated with better looks. (A caveat: One weakness of the study is that most of the participants, and all the artificial faces, were Caucasian.)

There you have it: Hoover up 3.3 more servings a day of fruits and vegetables and watch what happens.

It's really not a draconian move. In fact, study lead author Ross Whitehead, a psychology professor at the University of St. Andrews, calls it "relatively small." He has a point too, when you consider that the recommended quota of fruits and vegetables for someone consuming 2,000 calories is nine servings a day not including potatoes. And a serving isn't very big: about half a cup.

Judging by their generally woeful dietary habits, Americans are not currently maxing out in the appearance department, says Dr. David Heber, director of the UCLA Center for Human Nutrition and author of "What Color Is Your Diet?"

"Most Americans eat three servings of vegetables a day — iceberg lettuce, catsup and French fries," Heber says.

It's possible to go overboard, though. On carrots, for instance. Eat too many of those, Heber warns, and your skin, especially on your palms, can turn orange to a not necessarily lovely extent.